Relationship between pathological findings and values of haematological and blood-chemistry variables in apparently healthy finishing pigs at slaughter

Biochemical, carcass and meat quality alterations associated with different degree of lung lesions in slaughtered pigs

This study examined the relationship between lung lesion severity and presence of antibodies of various respiratory pathogens, and the effects of lung lesion severity on growth performance, biochemical indicators, total aerobe counts, and carcass and meat quality indicators in total of 240 slaughter pigs originating from two farms with similar rearing conditions. Lung lesion severity was calculated based on the degree of pneumonia and pleurisy in slaughtered pigs. Two-step cluster analysis was used to place individual pigs to four clusters according to pneumonia and pleurisy scores: no lung lesions (cluster 1); mild lung lesions (cluster 2); moderate lung lesions (cluster 3); and severe lung lesions (cluster 4). ANOVA and post hoc pairwise comparisons using Tukey's test were performed to assess the differences between clusters in examined variables. Multivariate linear regression analysis was run to identify associations between lung lesions and examined variables. There was a strong evidence of association between the absence of lung lesions and increased albumin, sodium and chloride levels, daily weight gain, live weight, hot carcass weight, cold carcass weight, loin thickness and carcass lean content, and decreased haptoglobin, CK and LDH levels. Also, pigs without lung lesions produced the highest percentage of red, firm and nonexudative pork. Pigs having severe lung lesions had the highest percentage of simultaneously seropositive samples to SIV, PRRSV, PCV-2, PRCV, APP and M. hyopneumoniae. There was a strong evidence of association between the presence of severe lung lesions and decreased lactate, glucose, sodium, chloride and albumine levels, daily weight gain, live weight, hot carcass weight, cold carcass weight, loin thickness and carcass lean content, and increased CK, LDH and haptoglobin levels. There was a strong evidence of association between the presence of severe lung lesions in slaughered pigs and increased meat pH and sensory colour scores, and decreased drip, thawing and cooking losses and L* and b* values, which led to the highest occurrence of moderate DFD and DFD pork. There was a strong evidence of association between the presence of mild lung lesions in slaughtered pigs and decreased meat pH and sensory colour scores, and increased drip, thawing and cooking losses, L* and b* values, which led to the highest occurrence of moderate PSE and PSE pork. In conclusion, the presence of lung lesions, irrespective of severity, was significantly associated with alterations in the biochemical indicators, growth performance and carcass and meat quality in slaughtered pigs.

Identifying Physiological Stress Biomarkers for Prediction of Pork Quality Variation

Simple Summary

Prediction of technological and sensory pork quality—during a pig’s life or quickly after slaughter—is increasingly required by the pork industry in order to classify carcasses or primary cuts of carcasses for different production lines. Therefore, there is increasing demand for the development of accurate, reliable, time-efficient, non-invasive, real-time tools for predicting pork and carcass quality characteristics. Based on this, the aim of this study was to assess the potential use of various physiological stress biomarkers as indicators of carcass and meat quality traits in slaughter pigs subjected to the standard marketing conditions and to minimal stressful preslaughter handling. According to the results of this investigation, lactate dehydrogenase can be considered as a useful predictor of pork quality, while cortisol, alanine amino transferase, and albumin could be useful in prediction of carcass quality.

Abstract

This study assessed the potential use of various physiological stress biomarkers as indicators of carcass and meat quality traits in 240 pigs subjected to the standard marketing conditions and minimal stressful antemortem handling using Pearson correlations. The most important pork quality traits (pH and temperature, water holding capacity, and color) had limited correlations with stress metabolites (lactate, glucose), stress hormones (cortisol, adrenocorticotropic hormone), stress enzymes (creatine kinase, aspartate amino transferase, alanine amino transferase), electrolytes (sodium, chloride), and acute-phase proteins (haptoglobin, C-reactive protein, albumin), indicating poor reliability in predicting pork quality. Albumin level was moderately positively correlated with live weight, hot carcass weight, cold carcass weight, and back fat thickness. Alanine amino transferase level was moderately positively correlated with live weight, hot carcass weight, and cold carcass weight. Cortisol level was moderately positively correlated with live weight, hot carcass weight, cold carcass weight, and back fat thickness, and moderately negatively correlated with the lean carcass content. Increased lactate dehydrogenase level was moderately correlated with decreased drip and cooking loss. In conclusion, lactate dehydrogenase could help pork producers predict pork quality variation, while cortisol, alanine amino transferase, and albumin could be useful in prediction of carcass quality.

Relationship between serum acute phase protein concentrations and lesions in finishing pigs

To establish the relationship between serum levels of three acute phase proteins, haptoglobin (Hp), C-reactive protein (CRP) and serum amyloid A (SAA), and the occurrence and severity of lesions at slaughter, a study was carried out using 70 fattening pigs from a finishing unit. Pigs were divided into three groups: Group 1 (25 pigs with clinical signs of disease), Group 2 (25 apparently healthy pigs with lesions at slaughter) and Group 3 (20 apparently healthy pigs with no lesions at slaughter). Serum levels of CRP, SAA and Hp were significantly higher in pigs with clinical signs of disease than in apparently healthy animals. Additionally, in apparently healthy pigs, serum levels of Hp and CRP were significantly higher in animals with lesions than those without lesions. The extent and severity of lung lesions were related to serum levels of Hp.

Nephelometric determination of haptoglobin plasma concentrations in fattening pigs

The haptoglobin plasma concentrations in 110 fattening pigs living on three commercial farms and in 28 animals on the university pilot farm were measured using a nephelometric detection method based on an immunoassay. Following calibration of the automated analyser (Nephelometer BN 100) with a human haptoglobin standard, the measurements were performed using anti-human antiserum from rabbits. Differences in age, gender or breed of apparently healthy animals seem to have no influence on the plasma concentration of the protein. The average plasma level of haptoglobin in animals suffering from acute respiratory diseases was significantly higher. Furthermore, an increase was observed in animals without clinical symptoms living on a farm characterized by obvious defects in housing conditions. Comparison studies of the nephelometric method by use of a human or porcine standard for calibration and different anti-human or anti-porcine antisera with radial immunodiffusion as a reference method resulted in high correlation coefficients for all variations. Optimal accuracy was obtained by calibrating the analyser with a porcine standard. Haptoglobin determinations have been shown to be a useful tool for health monitoring during the integrated pig-production process, allowing recognition of performance-reducing conditions. The immunonephelometric determination method is suitable for quantifying porcine plasma haptoglobin for routine checks. The use of animal-specific standards for calibration improves the accuracy of this method.

The porcine acute phase response to infection with Actinobacillus pleuropneumoniae. Haptoglobin, C-reactive protein, major acute phase protein and serum amyloid A protein are sensitive indicators of infection

In an experimental infection model mimicking acute Actinobacillus pleuropneumoniae (Ap) infection in swine (Sus scrofa) by aerosol inoculation, the development of a number of typical clinical signs was accompanied by a prototypic acute phase reaction encompassing fever and an acute phase protein response peaking at around 2 days after infection. Haptoglobin, C-reactive protein (CRP), and major acute phase protein (MAP) responded with large increases in serum levels, preceding the development of specific antibodies by 4-5 days. Serum amyloid A protein (SAA) was also strongly induced. The increase, kinetics of induction and normalization were different between these proteins. It is concluded that experimental Ap-infection by the aerosol route induces a typical acute phase reaction in the pig, and that pig Hp, CRP, MAP, and SAA are major acute phase reactants. These findings indicate the possibility of using one or more of these reactants for the nonspecific surveillance of pig health status.